Inlay-casting machine.



J. '11; JOHNSON & c. M. 1111111211111.

INLAY CASTING MACHINE nrmoumn mum 11211.25, 1908.

999,794. Patented Aug. 8, 1911. 2 SHEETWEBT 1.

[raven/0715 w ew (72m J1 Jazmsan 4 7% Ml ff I 77 i Jitwr'ngs J. A. JOHNSON & G. M. HEDMAN.

INLAY CASTING MACHINE.

APPLICATION FILED mums, 190a.

Patented Aug. 8, 1911.

Jim/*2 UNITED STATES PATEN T OFFICE.

JOHN A. JOHNSON AND CARL M. HEDMAN, OF CHICAGO, ILLINOIS.

INLAY-CASTING MACHINE.

' Specification of Letters Patent.

Patented All". 8, 1911.

Application filed April 25, 1908. Serial No. 429,142.

To all whom it may concern:

Be it known that we, JO N A. JOHNSON and CARL M. I-Innamx, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Inlay-Casting Machines, of which-the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

Our invention relates to casting machines, particularly to machines for casting inlays for dental work.

The object of our invention is to provide a better arrangement for the various parts constituting an inlay casting outfit. In prior outfits of this kind the various parts are separated, the pressure tank being connected with a pump by hose. The pressure tanks in these prior devices are also verylight and unstable.

One of the main features of our invention is the arrangement of the pump which is carried by the pressure or vacuum tank to form a unitary outfit, the tank being also heavy and more stable. The tank is substantially cylindrical, or barrel-slniped, and the pump preferably extends axially through the tank and secured therein, only the handle part being at the outside.

'Another feature of our invention involves the construction of the flask supporting cups. In prior devices these cups have beveled flanges for receiving the correspond ingly beveled ends of the flasks. The centcr part of these cups is also dished. or cupped out, so that when the filled flask is set on the cup, there will be an air space below the entire investment material within the (task.

In the use of the casting outfit, a mold of wax is first taken, for' instance of a tooth to be inlaid. This Wax is suspended in a flask, and investment compound or material, such as plaster of Paris, is poured about the mold or pattern. The material is allowed to set, and is thoroughly heated until it becomes hardened and the wax pattern on tirely absorbed thereby. The flask is then set on a cup, and gold or other material melted on top of the flask to find its way to the cavity left bythe pattern, suitable channels or gates having been provided thereto. After the inlay material has been heated sutficie'ntly, the cup is connected with the vacuum tank and the molten substance is sucked downinto the cavity to fill every niche and crevice and to form a perfect duplicate of the wax pattern and of the tooth cavity. The vacuum pressure exerted on a tlask is considerable, and where the cup flanges are beveled, as in the prior art, the flask is apt to become very tightly wedged in the cup and it is very ditticult to subsequently remove it; also, where the center of the cup is dished, the center of the investment material is unsupported and is apt to be drawn bodily out of the cup. The binding objection we overcome by making the flanges of the cup straight, and to insure a perfect fit between flask and cup, we turn a section of the cup and the edge of the flask so that the flask can be placed on the cup to make an airtight connection. Also, instead of dishing the center of the cup, we leave the lloor of the cup horizontal, and provide intersecting radial and concentric grooves therein, which are all connected with the passageway leading to the vacuum tank. Thus, the pressure is accessible to all parts of the flask, and still the investment material is perfectly supported. In the accompanying drawings of our invcntioinit is clearly illustrated.

Figure 1 is a front view; Fig. 2 is a side view; Fig. 3 is a sectional view taken on vertical plane 3, of Fig. 1;- Fig. =1 is a large top view of one of the cups; Fig. 5 is an enlarged view of the end section of the pump, showing the valve mechanism; F ig. (i is a sectional view taken on plane ti, 6, of Fig. 5, and Fig. T is an enlarged plane view of the valve disks which we employ.

The pressure vacuum tank 1 may be cylindrical, or more or less barrel-shaped, as

shown, being provided with feet 2, 2 by means of which it may be rigidly secured to a support, if deemed. The cylindrical pump 2 which we employ comprises the 100 pump barrel 3 having the guide head t for the piston rod Tnand at its other end closed by the valve frame-6. The outer end of the piston rod terminates in the handle or knob 7, while at the other end is secured the 105 leather plunger 8 between outer and inner washers 9 and 10 and nuts 11 and 12. The valve frame 6 has the inner bore section 13, the intermediate bore section 14 of larger diameter, and the outer threaded bore sec;; 110

tion 15. A nut 16 engages this threaded portion, and has the passageway 17. With-' in the bore part or compartment 14;is the valve disk 18, whose form is best shown in Fig. 7. This disk is formed by cutting semi-circular sections or segments from. the edge of a circular disk, to leave the by passes 19. hen the pump rod is pulled out, air is withdrawn from the tankinto the pump barrel, the valve disk during this outward movement of the plunger resting against the shoulder or seat 19', at the left endof valve compartment 14, and the air can flow from the tank through the byspring 22 encircles the pumprod andacts passes 19 and into the pump barreL- When the plunger comes to'rest or is moved rearwardly, the valve disk is thrown against the inner, face of the nut 16, this .face being --within the by passes 19, so that the passageway 17 will be closed,'the reduced pressure in the tank being thereby maintained. The air which was drawn into the barrel upon outward movement of the plunger will pass by the flexible plunger edges when the plunger is moved inwardly. Upon outward movement of the plunger, anyair in front thereofescapes to the outside through pas sageways 20 through the head 4. Thus as the pump is operated,; the air will be'exhausted from-the tank, .the pressure threin being indicated by a pressure gage 21 suitably mounted on the tank. A buffer as a cushion for the plunger when the plunger reaches the outer end of the barrel.

The valve mechanism for the pump which we'have' described is very simple and very eificient. 'Brazed to the front end of the pump barrel is a sleeve 23 having a threaded portion. 24: for engaging in the threaded opening 25 through the front head of the tank, the outer portion of the sleeve being'polygonal, so that a wrench may be 'alpplied. A washer 26 of lead or other suit.-

"The entirepump structure can readily be ger removed. By unscrewing is material is interposed, in order that an airtight fit will result. The rear end of the pump extends into and is supported in a niche 27 in the rear head of the tank.

unscrewed bodilyfrom the tank, and upon removing the screw or screws 28, the head 4: can be withdrawn and the stem and plunthe nut 16, the valve can be removed.

A T-member '29 is screwed into theto'p of the front end of the tank, and at its ends engages with valve members 30 and 31 terminating in elbow members 32and 33, respect1vely.- Mounted .on elbow 32 is the cup member 34, and-mounted on elbow 33 is the .cup' member 35. Each cup member has a vertical flange 36 and-a planed horizontal annular section 37,'form ing aseat for a flask framed-38, whose lower edge is also planted to form an airtight j'cintlwith the cup surface37. The inner section; of. -thel cup basehas concentric 39 an inter secting radial grooves 40, these grooves being all in connection with the passageway 41. leading through the cup member and through the various connecting members with the [tank when the corresponding valve is open. The lower edge. of each. flask also extends inwardly a slightdistance, to give I greater bearing surface and also to'form a ledge 42 for assisting to hold'theinvestment material within the flask. i A fterthe-pattern or mold has been suspended-in the flask and the compound sufficiently dried and hardened, the flask is placed on its cup and heated, to' cause absorption of the wax..

Gold or other suitable inlaying material is then laid at the entrance of the passageways to the cavity leftby'the melted wax,;and is thoroughly heated to a liquid-state, when the corresponding valve is opened and the .cup connected with the low-pressure. This flask can be readily removed from the cup.

We have shown twocups for accommodating twodifferent sizes of flasksgbut of course any number of cups could be provided. We thus have a unitary self-com. tained outfit, all the parts necessaryforforming inlays being united. The outfit can be made sufficiently heavy to bestable. The

tankcan also be fastened to a support by means of screws or nails passing through the feet. In dental work, -many other applianee s areused during work on a patient,

such as 'a'carbureter, for instance, for supplying gas. "Devices of this kind are usually small and easily misplaced, besides being very unstable. I Our tank body would form a very eflicient support for devices of this land, Flg. 1 showing a .carbureter C supported fromo'n'ess'ide of the tank." 4 We do not wish to' be limited to the exact construction which we have shown and de-- scribed, as changes and ,modifications are poss ble which will come within the scope of our invention, the main features of which being :the rigid connection of the pump' directly with theptank and the improved form of cupand flask;

Hayingthusdescribed our invention, we

desire to. secure the following claims by LettersiiPatentz' i ;1.-In-a device of the class described, the

the pi'essure withinsaid tank, a'supporting -combination of a'tank, means for adjusting c'up, va.1ve mechanism for-controlling the connection of said cap with the tank, and' intercommunicating radial grooves in' the base of said cup.

2. In a'device of the class described, the; combination of a tank,'means foradjustin'g" thepressure in said tank, and a supporting? cup adapted for connection with the tanki the base of said cup being horizontal a a provided with intercommunicating grooves 10 aving connection with the passageway and thereby with the tank.

l 3'. In a device of the class described, the

combination with a vacuum tank, of a cup supported on said tank and adapted for communication therewith through a passageway, the base of the cup being'in a horizontal plane and provided with concentric and radial intercommunicating grooves connected with the passageway and thereby with the tank.

4. In a device of the class described, the combination of a vacuum tank, a flask suporting cup mounted on said tank and havmg connection therewith through a passage way, the base of the cup being in a horizontal plane, the outer section of said cup I --being planed and finished to be engaged with airtight fit by the finished edge of-a flask supported by the cup, the inner section of Copies of this patent may be obtained 1'01 the basebeing provided with grooves havingconnection with said passageway.

:5. In combination, a vacuum tank, a supporting cup, and a valve for controlling the connection of saidcup with the tank, said radial cup havin intercommunicating grooves in t e base thereof.

. 6. In combination, a vacuum tank, a supportingcup, and a valve for controlling the connection of said cap with the tank, the

base of said on being substantially horizontal and rovided'with intercommunicating grooves avin'g connection with the tank. In combination, a vaciiu'm' tank, a su porting cup, and avalve for controlling t 1e c onnection of said-cup withthe tank, said cup having inter-communicating grooves in the base thereof. l

8. In combination, a vacuum tank, a supporting cup, and a valve for controlling the v five cents each, by addressing the. Commissioner 0! Patents, Washington, D. 0. 

